#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<string>
#include<iostream>
#include<vector>
#define LL long long
#define INF 0X7FFFFFFF
using namespace std;
int T,N;
int f[100005];
int s[100005];
int ss[10];
inline bool cmp(int a,int b)
{
    return a>b;
}
int main()
{
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&N);
        memset(s,0,sizeof(s));
        for(int i=1;i<=N;i++)
        {
            scanf("%d",&f[i]);
            if(i!=1) s[i-1]=abs(f[i]-f[i-1]);
        }
        sort(s+1,s+N+1,cmp);LL ans=0;
        for(int i=1;i<=N;i++)
        {
            int af=abs(f[i]-f[i-1]);
            if((i-1)==0) af=-1;
            int bf=abs(f[i]-f[i+1]);
            if(i+1>N) bf=-1;
            for(int j=1;j<=3;j++)
            {
                ss[j]=s[j];
        //        cout<<"*"<<ss[j]<<' ';
            }
        //    cout<<endl;
            int tmp=0;
            for(int j=1;j<=min(3,N-1);j++)
            {
                if(af==ss[j])
                {
                    af=-1;
                    ss[j]=-1;
                    continue;
                }
                if(bf==ss[j])
                {
                    bf=-1;
                    ss[j]=-1;
                    continue;
                }
            //    cout<<ss[j]<<' ';
                tmp=max(ss[j],tmp);
            }
            //cout<<endl;
            if(i-1==0||i+1==N+1) ans+=tmp;
            else
            {
                tmp=max(tmp,abs(f[i-1]-f[i+1]));
                ans+=tmp;
            }
        //    cout<<ans<<endl;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}